Mid-wave infrared interband cascade photodetectors and focal plane arrays based on InAs/GaSb superlattices

In recent years, type-II InAs/GaSb superlattices (T2-SLs) have demonstrated dramatic advances and are a serious contender for the high performance infrared (IR) imaging market. The improved understanding of the material properties, as well as the implantation of advanced device architectures, has substantially improved the device performance. Here we will report our efforts to develop mid-IR type-II T2-SL photodetectors and focal plane arrays based on interband cascade structure. The interband cascade photodetector exploits the energy band alignment in the nearly lattice-matched “6.1-Å-family” (InAs, GaSb, AlSb, and their alloys) material system. The InAs/GaSb T2-SL is adopted as the absorber, and two unipolar barriers are placed at each side of the absorber.